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Antipsychotic
Antipsychotics (APDs, also known as neuroleptics) are agents that relieve psychosis (hallucinations and delusions), they usually work by antagonizing the dopamine D2 receptors. They include atypical antipsychotics and typical antipsychotics. The latter, older agents produce significant movement side effects,Including stiffness, involuntary movements, tremor, rigidity, etc. whereas the newer ('atypical') agents produce less movement side effects. Available agents Explanatory notes Superscripts: Agents that are approved by the Australian are given a T superscript, colon (:) the year of TGA approval (note: this date information gets a little fuzzy before the 1990s as the TGA was formed in 1989), hence may not be given. Agents that are approved by the American are given a F superscript, colon (:) the year of FDA approval. Whereas agents that are approved by the British are given M superscripts with the date of first MHRA approval. Note, however, that the MHRA was first formed in 2003, when two agencies merged, hence if the product was first marketed prior to this time figures may be inaccurate. Discontinued agents are assigned asterisks in the superscripts, after the superscript of the respective administration that has revoked its approval. QT interval is a part of the heart's electrical cycle, usually measured using an electrocardiogram (ECG). If it prolonged it can lead to sudden and unexpected death. Anticholinergic side effects are related to the body's involuntary muscles. : Includes: :*Dry mouth :* Constipation :* Nausea/vomiting :* Blurred vision :* Reduced sweating :* Reduced urinationAs some involuntary muscles are required for urination :* Metabolic changes Including: blood sugar changes (usually increases), diabetic ketoacidosis (a condition caused by dangerously utilization of blood sugar that leads to brain damage and death) and type II diabetes mellitus. Depends on which cholinergic receptors it binds to and other factors too Antihistamine side effects mean things like: drowsiness, weight gain, metabolic changes (making one more likely to develop metabolic syndrome), etc. Adrenergic side effects include: orthostatic hypotension (dizziness upon standing up, due to drops in blood pressure), drowsiness, dizziness, etc. They usually relate to blood pressure and refer to the blocking of α1 receptors. Prolactin, is a hormone that regulates breast growth and lactation. Prolactin secretion from the pituitary gland (near the centre of the skull) normally stimulates the breast tissue to grow, and produce milk. It does not cause them to release milk (that is caused by a hormone called oxytocin). Its release is inhibited by the neurotransmitter, dopamine. Dopamine is released by the hypothalamus, which, in order inhibits prolactin release. References are usually found on the agent's respective page on this Wiki which is hyperlinked. Atypical agents * Amisulpride'''M: 1997; T: 2002 (brand names: Amipride, Solian, Sulprix), a '''benzamide agent that possesses minimal affinity towards the 5-HT2 receptors, or histamine/cholinergic receptors. It produces significant elevation in prolactin levels, weight gain (although less than clozapine, olanzapine, quetiapine, risperidone or zotepine; fairly unprone to cause type II diabetes mellitus), QT interval prolongation (less than sertindole or pimozide) and movement disorders (less than the typical agents, but still more than clozapine or quetiapine). It is generally not sedating, neither are adrenergic and anticholinergic side effects. It is not marketed in the U.S.A. or Canada. Lower doses are also used in some countries to treat dysthymia. It was first introduced in the 1990s. * Aripiprazole'''F: 2002; M: ?; T: 2003 (brand names: Abilify, Aripiprex) is a '''quinolinone derivative that serves as a potent partial agonist at the D2 receptors. Movement disorders are infrequent, although akathisia is common. It causes reduced prolactin levels and is (tied with amisulpride) one of the least prone of atypicals for causing weight gain or sedation. It is indicated for the treatment of bipolar mania, bipolar maintenance, an adjunct in major depression (that is, as an add-on agent, taken on top of antidepressants; only indicated for this use in the U.S.A.) and schizophrenia. * Asenapine'''F: 2009; M: ?; T: 2011 (brand names: Saphris, Syncrest) is a '''tetracyclic atypical agent that has a lower incidence of weight gain or sedation (although it is more sedating than amisulpride, aripiprazole, sulpiride and ziprasidone). Chemically it is a tetracyclic agent. It was first approved in 2009. It is administered twice daily under the tongue. * Blonanserin (brand name: Lonasen) is an 4-phenyl-2-(1-piperazinyl)pyridine agent 'that is sold solely in Japan and South Korea. It is used to treat schizophrenia in two divided doses. It is tetracyclic although its chemistry is distinct from clozapine, quetiapine and olanzapine. * 'Clozapine'''F: 1989; M: 2008; T: 1994; W (brand name: Clozaril) is a '''dibenzodiazepine atypical antipsychotic that was first synthesized in 1958, introduced to certain European countries in the 1970s, it was later withdrawn from the market after fatal cases of agranulocytosis were reported. It is especially effective in treatment-resistant cases. * Iloperidone'''F: 2009 (brand name: Fanapt) is a '''benzisoxazole atypical antipsychotic that is used to treat schizophrenia. * Lurasidone'''F: 2010; T: 2014 (brand name: Latuda) is a '''benzisothiazole atypical antipsychotic that antagonizes the D2, 5-HT2A and 5-HT7 receptors and partially agonizes the 5-HT1A receptors, it is purported to be particularly effective at relieving the negative and cognitive symptoms of schizophrenia. * Melperone (brand names: Bunil, Buronil) is a butyrophenone agent with a particularly low incidence of movement disorders, weight gain, sedation and prolactin elevation. It has been purported to possess unique efficacy in the treatment of treatment-resistant patients. It is only marketed in a few European countries. * Perospirone (brand name: Lullan) is an azapirone agent purported to have a higher incidence of movement disorder side effects than other atypicals and a lower efficacy in treating schizophrenia. * Quetiapine'''F: 1997; M: ?; T: 2000 (brand names: Seroquel and many others) is a '''tetracyclic agent that, similarly to clozapine, produces minimal movement disorder side effects due to its very low affinity towards the D2 receptors, but unlike most other atypicals its affinity towards the 5-HT2A is about five fold less than its affinity towards the D2 receptor. It is used to treat a variety of conditions, including: major depression (usually as an adjunct to standard antidepressants in cases of non-response; it is the only medicine that is -approved for use as an adjunct in major depression), bipolar disorder (including in bipolar depression, mania and maintenance) and schizophrenia. * Risperidone'''F: 1993; M: ?; T: 1993 (brand names: Risperdal and others) is a '''benzisoxazole atypical with a relatively high affinity (for an atypical) towards to the D2 receptors, it produces more movement disorder side effects than most other atypicals. It inverse agonizes the 5-HT2A about 20 fold more potently than it antagonizes the D2 receptors. It elevates prolactin amongst the most of all antipsychotics, and is less sedating and prone to cause weight gain than tetracyclic antipsychotics. Typical agents * Benperidol'''M: 2006 (brand name: Anquil) is a butyrophenone antipsychotic''' of the typical class that is also used to treat deviant sexual behaviour, although in some countries it is used to treat schizophrenia. It is marketed in the U.K., but has never been marketed in Australia or the U.S.A. * Bromperidol (brand names: Bromidol, Bromodol and Impromen) is a butyrophenone antipsychotic of the typical class that is used to treat schizophrenia and other psychoses, but not in any English-speaking country. * Carpipramine (brand names: Defekton, Prazinil) is a pentacyclic antipsychotic, that is chemically related to the . It used solely in France and Japan, it is dosed 2-3 times daily. * Chlorpromazine'''F:1957; M: ?; T: 1991; W (brand names: Largactil, Thorazine) is a '''phenothiazine antipsychotic of the typical class it is used to treat schizophrenia, bipolar mania, severely disturbed, agitated or violent behaviour, anxiety, nausea and vomiting, intractable hiccups, tetanus, acute intermittent porphyria or hypothermia (low body temperature). It was the first APD to be developed, it is very sedating, prone to causing movement disorders, elevated blood prolactin levels and causes weight gain in a number of patients. * Chlorprothixene'''W (brand names: Taractan, Tarasan) is a '''thioxanthene antipsychotic of the typical class, it is used to treat schizophrenia and other psychoses. It is administered 3-4 times a day. * Clocapramine'W (brand names: Clofekton, Padrasen) is an antipsychotic related to carpipramine. It is used in the treatment of schizophrenia in Japan only. * '''Clotiapine'W (brand names: Entumine, Etomine, Etumine and variants) is a '''tetracyclic antipsychotic chemically related to clozapine, olanzapine and quetiapine that is used to treat schizophrenia, bipolar mania and anxiety. It used in a few European countries, Argentina, Israel and South Africa. It is chemically related to clozapine, olanzapine and quetiapine. * Dixyrazine (brand name: Esucos) is a phenothiazine antipsychotic that was marketed in a few European countries and South Africa; now just marketed in Italy. * Droperidol (brand name: Droleptan, Inapsine) is a butyrophenone antipsychotic that is primarily used nowadays to treat nausea/vomiting after surgery. It was once available in many countries as a treatment for schizophrenia, nowadays, however, it is no longer marketed for this purpose due to concerns over its potential for prolonging the QT interval. * Flupentixol (flupenthixol; brand names: Depixol and Fluanxol) is a thioxanthene antipsychotic of the typical class. It is usually given via depot injections when used to treat schizophrenia, although it may also be given orally (although this preparation is not available in Australia). Lower doses are also used to treat dysthymia. * Fluphenazine'''W (brand name: Modecate) is a '''phenothiazine typical antipsychotic that is given via depot injections and that is notably devoid of anticholinergic, antihistamine and adrenergic activity. * Fluspirilene (brand name: Imap, Redeptin) is a diphenylbutylpiperidine antipsychotic usually given in depot injections that is less sedating than chlorpromazine but has properties that are generally the same. * Haloperidol'''F: 1967; M: 1996; T: 1991; W (brand name: Haldol, Serenace) is a '''butyrophenone typical antipsychotic that is notably devoid of anticholinergic, antihistamine and adrenergic activity. Movement disorders are usually severe with it. * Levomepromazine'''M: 1999 (brand names: Apo-Methoprazine, Levinan, Novo Meprazine, Nozinan) is a very sedating '''phenothiazine typical antipsychotic that is used in palliative care (as it has painkilling and antiemetic effects). * Loxapine'''F:1975; M:?* (brand names: Adasuve, Loxipac, Loxitane) is a '''tetracyclic typical antipsychotic that is given via inhalation (only available in the U.S.A.), tablets or by intramuscular injection. It is metabolized to amoxapine, a tricyclic antidepressant. It is given in 2-4 divided daily doses. * Molindone'''F: 1974 (brand name: Moban) is an '''indole derivative that produces weight loss instead of weight gain; it is solely available in the U.S.A. * Periciazine'''M: <2009; T: 1991 (pericyazine; brand name: Neulactil) is a '''phenothiazine agent that is used primarily in the short-term management of severe anxiety, disturbed behaviour and the management (both short-term and long-term) schizophrenia and other psychoses. * Pimozide'''F: 1984; M: <1997; T: ?* (brand name: Orap) is a '''high potency diphenylbutylpiperidine antipsychotic used primarily to treat Tourette's syndrome in the U.S.A., in other countries (like the U.K.) it is used to treat schizophrenia and other psychoses. It is notorious for causing QT interval prolongation; it was once marketed in Australia but it is no longer, likely due to its potential for QT interval prolongation. It is one of only two APDs that is associated with weight loss (although this has not reached statistical significance) instead of weight gain. * Thioridazine'''F: 1962; M: <2005*; T: <2005* (brand name: Mellaril, Melleril) is a '''phenothiazine antipsychotic that has similar properties to chlorpromazine but is associated with a higher incidence of anticholinergic side effects, QT interval prolongation, drowsiness and a lower incidence of movement disorders. There has been renewed interest in its use as a treatment for totally/extensively-drug resistant cases of tuberculosis as it increases the sensitivity of the bacteria that causes the disease to anti-TB drugs that is has since evolved resistance to. * Zuclopenthixol (brand names: Clopixol) is a high-potency thioxanthene antipsychotic typically given orally or via intramuscular injections (including as depots. Chemistry Butyrophenones Butyrophenones tend to be very insoluble in water. Very fat soluble, however. Hence why some (like haloperidol) come as fatty acid esters (e.g., decanoate for haloperidol). One is on the . They are generally high potency. Diphenylbutylpiperidine R1 is cyclical for most drugs. They are also very fat soluble and water insoluble. They are all high potency typical agents, not one is on the . Phenothiazines Phenothiazines are very soluble in organic solvents and very insoluble in water. Very fat soluble, however. Two are on the . Category:Antipsychotics Category:Schizophrenia Thioxanthene Where R1 is subject to cis/''trans''-isomerism. Not one is on the . Multicyclics For multicyclics the structure varies quite significantly; hence, some examples are shown. They are very fat soluble, water insoluble and can be used to form fatty acid esters (e.g. olanzapine embonate for injection). Only one is on the (clozapine). External links Notes Reference list Category:Antipsychotics Category:Schizophrenia